This invention relates to novel steroids and more particularly to androsterone derivatives useful as anti-cancer, anti-obesity, anti-diabetic and hypolipidemic agents.
Dehydroepiandrosterone (DHEA) and DHEA-sulfate are major adrenal secretory products in humans. The plasma concentration of DHEA-sulfate, which, next to cholesterol, is the most abundant steroid in humans, undergoes the most marked age-related decline of any known steroid.
Although DHEA-sulfate is the main precursor of placental estrogen and may be converted into active androgens in peripheral tissue, there is no obvious biological role for either DHEA or DHEA-sulfate in the normal individual. Several retrospective and prospective studies suggest that women with sub-normal levels of these steroids may be predisposed to develop breast cancer. For example, see Brownsey, et al., "Plasma dehydroepiandrosterone sulfate levels in patients with benign and malignant breast disease, Eur. J. Cancer, 8, 131-137 (1972); Bulbrook, et al., "Relation between urinary androgen and corticoid excretion and subsequent breast cancer, "Lancet, 2, 395-398 (1971); Rose, et al., "Plasma dehydroepiandrosterone sulfate, androstenedione and cortisol, and urinary free cortisol excretion in breast cancer, "Eur. J. Cancer, 13, 43-47 (1977); Wang, et al., "Studies of the sulfate esters of dehydroepiandorsterone and androsterone in the blood of women with breast cancer," Eur. J. Cancer, 10, 477-482 (1974); and zumoff, et al., "Abnormal 24-hr mean plasma concentrations of dehydroisoandrosterone and dehydroisoandrosterone sulfate in women with primary operable breast cancer," Cancer Research, 41, 3360-3363, September 1981.
It has also been established that DHEA is a potent non-competitive inhibitor of mammalian glucose-6-phosphate dehydrogenase (G6PDH). For example, see Oertel, et al., "The effects of steroids on glucose-6-phosphate dehydrogenase," J. Steroid Biochem., 3, 493-496 (1972) and Marks, et al., "Inhibition of mammalian glucose-6-phosphate dehydrogenase by steroids," Proc. Nat'l Acad. Sci, U.S.A., 46, 477-452 (1960). Moreover, Yen, et al., "Prevention of obesity in A.sup.vy /a mice by dehydroepiandrosterone," Lipids, 12, 409-413 (1977), reported that long-term administration of DHEA to VY-A.sup.vy /a mice prevented the development of obesity without suppressing appetite.
Furthermore, it is also known that the long-term treatment of C3H mice with DHEA, in addition to reducing weight gain without suppressing appetite, markedly inhibits spontaneous breast cancer development and may delay the rate of aging. It has been observed that DHEA antagonizes the capacity of the tumor promoter, 12-0-tetradecanoylphorbol13-acetate, to stimulate .sup.3 H-thymidine incorporation in mouse epidermis and in a cultured rat kidney epithelial cell line. See, Schwartz, "Inhibition of spontaneous breast cancer formation in female C3H-A.sup.vy /a mice by long-term treatment with dehydroepiandrosterone, Cancer Res., 39, 1129-1132 (1979); and Schwartz, et al., "Dehydroepiandrosterone: and anti-obesity and anti-carcinogenic agent," Nut. Cancer 3, 46-53 (1981).
Ben-David, et al., "Anti-hypercholesterolemic effect of dehydroepiandrosterone in rats," Proc. Soc. Expt. Biol. Med., 125, 1136-1140 (1967) have observed that DHEA treatment has an anti-hypercholesterolemic effect in mice, while Coleman, et al. (Diabetes 31, 830, 1982) report that administration of DHEA produces a marked hypoglycemic effect in C57BL/KsJ-db/db mice. The latter authors suggest that the therapeutic effect of DHEA might result from its metabolism to estrogens.
It is further known that DHEA and 16-bromo-epiandrosterone are inhibitors of Epstein-Barr virus-induced transformation of human lymphocytes and that 16-bromo-epiandrosterone is a more potent inhibitor of mammalian G6PDH than DHEA. See, Schwartz, et al. Carcinogensis, Vol. 2 No. 7, 683-686 (1981).
While DHEA has been found effective in the afore-described manners, there is however, evidence of an estrogenic effect after prolonged administration. DHEA is not an estrogen per se but is well known to be convertible into estrogens. In addition, the therapeutic dose of DHEA is rather high. It would therefore be highly desirable to provide steroids, which while having the same afore-described advantage of DHEA are more potent and do not produce an estrogenic effect.